The present invention relates generally to the interfacing with computer and mechanical devices by a user, and more particularly to devices used to interface with computer systems and telemanipulator devices and which provide haptic feedback to the user.
Humans interface with electronic and mechanical devices in a variety of applications, and the need for a more natural, easy-to-use, and informative interface is a constant concern. In the context of the present invention, humans interface with computer devices for a variety of applications. One such application is the control of telemanipulator devices to interface with physical environments. Other applications include interacting directly with computer-generated environments such as simulations, games, and application programs.
Telemanipulator devices are often used for remote manipulation of physical objects and items in areas that can be difficult or unavailable for humans to operate directly. For example, telemanipulator devices can be used in hazardous environments, such as radioactive areas or extremely hot areas, to manipulate items in that environment. Other areas where these devices are commonly used include underwater or the ocean, outer space, areas having poisonous gasses in the air, etc. With these devices, exploration of an environment, retrieval of samples from the environment, or operation and maintenance of equipment within the environment can be performed with little risk to humans.
A typical telemanipulator includes a master end effector (or xe2x80x9cmasterxe2x80x9d) and a slave unit (or xe2x80x9cslavexe2x80x9d). An operator or user manipulates the master device in provided degrees of freedom, control signals are transmitted from the master to the slave, and the slave is moved and manipulated in a fashion corresponding to the manipulation of the master. In some telemanipulator devices, the slave sends back information to the master indicating a present state of the slave or providing information about the slave""s environment. The slave is commonly a robot arm having one or more instruments or devices attached to the arm. For example, a parallel jaw gripper can be attached to the robot arm and moved within the slave""s environment to grasp, pick up, and move objects. Alternatively, or additionally, the slave end effector can include a camera, light source, welding torch, wrench, screwdriver, cutting blade, or other instrument. The slave can be mounted on a static surface, or can be placed on a mobile entity such as a vehicle that can be, for example, piloted using remote control. A computer is preferably used to interface the master with the slave, to provide appropriate signals in bidirectional communication, and perform processing of signals or automated control of the slave when necessary.
The master end effector can take a variety of forms. One configuration uses a joystick-like controller to manipulate the slave. The operator moves the joystick handle in two or more degrees of freedom, which moves designated portions of the slave in corresponding degrees of freedom. One problem with joystick master controllers is that the control of the slave is not very intuitive, and achieving proficiency with this type of master requires considerable operator training. Other master end effectors are more intuitive for the operator. Exoskeletons or linkages can allow an operator to make movements with the master that cause closely-corresponding movements of the slave. For example, a grip can be attached to a linkage having six degrees of freedom, and the grip can be moved and rotated in space in a fashion that the operator wishes the instrument on the slave to move and rotate.
In some telemanipulator devices, force feedback or tactile feedback is also provided to the user, more generally known herein as xe2x80x9chaptic feedback.xe2x80x9d These types of telemanipulator devices can provide physical sensations to the user manipulating the master end effector. When the slave impacts a surface or other obstruction, or otherwise interacts with its environment, it is desirable that the operator sense this interaction. Thus, forces provided on the master end effector can help the operator guide and operate the slave more effectively. If the slave impacts a wall, a force corresponding to what the slave experiences can be output on the master end effector using motors or other actuators of the master device.
One problem with haptic feedback used in master end effectors of the prior art is that the haptic feedback provided to the operator concerning the interactions of the slave with its environment is very limited and/or not well correlated to fine control of the slave, so that the operator receives only a crude sense of what is happening in the slave environment. For example, higher frequency tactile cues such as occurs when two hard objects contact each other are omitted. Furthermore, for slave devices having a jaw gripper, there is no haptic feedback provided to the operator concerning the movement and interaction of the jaw gripper with other objects. In addition, current equipment for teleoperation can be expensive and often has reliability and stability problems in harsh environments such as underwater oil rig maintenance.
Another problem is the degree of control provided to the operator over the slave device. Master control over such slave instruments as a gripper is often crudely performed with devices such as buttons and triggers, which do not greatly help the operator manipulate the gripper to perform highly delicate operations, and do not provide an intuitive control mechanism.
In other interface applications, the user interacts not with a physical environment, but with a computer generated or virtual environment. For example, in virtual reality applications or computer games, an interface device is coupled to a host computer which is running an application program that provides an environment, such as a graphical environment. The computer generated environment is displayed on a device such as a computer display. The user manipulates controls such as a manipulandum joystick handle, mouse, etc.), buttons, switches, or the like, and sensors detect the manipulation and input signals to the host computer to allow corresponding manipulation of graphical objects displayed on a display screen. Haptic feedback can be added to such interface control devices to provide the user with a more interactive experience and to provide greater ease in interfacing and controlling computer-generated objects and environments. A problem with current haptic feedback devices, however, is that the haptic feedback is not very well integrated into some types of controllers, such as gamepads or other controllers besides traditional joysticks.
The present invention provides a haptic feedback control device which includes several improvements to the interface with computer systems and the control of objects. The controller device includes a force feedback pincher mechanism that provides a more natural control over physical or computer-implemented objects. A moveable portion of the housing allows tactile feedback independent of other controls to be output to the user.
More particularly, in one aspect of the present invention, a haptic feedback control device for inputting control signals to a computer and for outputting forces to a user of the control device includes a grip and a pair of moveable pincher members coupled to the grip. Each pincher member is contacted by a finger of the user when the device is operated, where each of the pincher members are moveable in a degree of freedom and the degrees of freedom are approximately within a single plane, such that when one of the pincher members is moved, the other pincher member is also moved approximately the same distance either towards or away from the first pincher member. An actuator is coupled to the pair of pincher members and is operative to output a force on the pincher members in the degree of freedom. A sensor is operative to detect a position of the pincher members in the degree of freedom and output a sensor signal indicative of the position which is received by the computer. Each of the pincher members preferably includes a finger pad for receiving a finger of the user, where the user operates the device by placing a thumb on one of the finger pads and an opposing finger on the other finger pad. The actuator outputs a linear force in a linear direction which is converted to a rotary force that is applied to each of the pincher members.
In a different aspect of the present invention, a haptic feedback control device inputs control signals to a computer and outputs forces to a user of the control device, and includes a housing including a fixed portion and a moveable portion, where the user grips both the fixed and moveable portions when using the device. A coupling, such as a flexure, is coupled between the moveable portion and the fixed portion and allows the moveable portion to move relative to the fixed portion in a direction parallel to a portion of an outer surface of the moveable portion that is contacted by the user. An actuator is coupled to the flexure and outputs a force on the flexure to cause the moveable portion to move with respect to the fixed portion. Preferably, the actuator outputs an oscillating force to cause the moveable portion to vibrate. A preferred embodiment of the device includes a control manipulable by the user and positioned on the moveable portion such that the user feels the force on said moveable portion as tactile feedback when operating the control, and where the control is fixed in position with reference to the moveable portion. For example, the control can be the force feedback pincher mechanism of the present invention or a portion thereof, or can be a button, joystick, or other control.
In one embodiment, the haptic feedback control device of the present invention that includes any of the above aspects is a master device in a telemanipulator system such that the grip is coupled to a linkage of a plurality of members that provides at least three degrees of freedom of motion to the control device, and where the computer controls a slave device in conjunction with motion of the master device. The slave device can include an arm linkage and an opening/closing gripper, where the gripper is controlled by the pincher members. In a different embodiment, the computer displays a graphical environment which with the user interacts using the force feedback control device of the present invention, such as a computer game, graphical user interface, or medical simulation. A local microprocessor can also be included in the control device that receives the sensor signal, reports the sensor signal to the computer, and controls low-level signals to the actuator. Other controls can also be included on the control device, such as a roller that is sensed by a sensor.
In another embodiment, a haptic feedback interface device includes a joystick having two degrees of freedom and a linkage coupled to the joystick for providing the two degrees of freedom. First and second grounded linear voice coil actuators are coupled to the linkage and apply a force to the joystick through the linkage, where a linear motion of a bobbin of the first actuator is approximately parallel to a linear motion of a bobbin of the second actuator. Preferably, the force output by one of the actuators is approximately parallel in direction with respect to a force output by the other actuator, and the forces are approximately orthogonal in direction with respect to a plane formed by two axes of rotation of the joystick.
A method of the present invention for controlling an object with a haptic feedback control device includes outputting a control signal to a computer, the control signal including information describing a manipulation by a user of the haptic feedback control device. The manipulation includes moving a finger pad of the control device in a degree of freedom such that the information in the control signal includes a representation of a position of the finger pad in the degree of freedom. Haptic feedback signals are received from the computer that include information causing a force to be output on the finger pad in the degree of freedom. The force feedback signals also include information causing a vibration of a moveable portion of a housing of the control device surrounding the finger pad. The vibration is preferably caused when the object controlled by the control device interacts with a different object. The object controlled by the user can be a computer-generated object displayed on a display screen or a physical object such as a slave unit in a telemanipulator system.
The improvements of the present invention provide a more natural haptic feedback interface device that is intuitive and easy to operate. The pincher mechanism of the present invention allows a user to easily control objects such as a gripper or virtual hand, and provides haptic feedback based on interactions of the controlled object to allow more detailed and accurate control. The moveable portion of the housing of the present invention provides another channel through which the user can experience haptic feedback independently of any other control mechanisms such as the pincher mechanism, allowing the user to experience feedback concerning interactions of the controlled object to a greater extent, which allows even further natural and accurate control of the object.
These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following specification of the invention and a study of the several figures of the drawing.